The present invention relates, in general, to the field of signal transmitting and receiving range-finding devices. More particularly, the present invention relates to a high precision, high performance optical system and beam pathway design for laser-based distance measuring, or range-finding, devices.
Representative implementations of optical pathways for various optical instruments, including laser-based rangefinders, are described in, for example, U.S. Pat. No. 6,236,504 issuing May 22, 2001 for “Method and Device for Adjusting Eye Range by Means of Displacements of Prisms and Ocular Lenses”; U.S. Pat. No. 6,292,314 issuing Sep. 18, 2001 for “Prism System for Image Inversion in a Visual Observation Beam Path”; and U.S. Pat. No. 6,344,894 issuing Feb. 5, 2002 for: “Optical Axis Adjusting Structure for a Range Finder”. A design representing a decided improvement over those described in the afore-mentioned issued patents is disclosed in U.S. patent application Ser. No. 10/992,572 filed Aug. 20, 2004 for: “Efficient Optical System and Beam Pathway Design for Laser-Based Distance Measuring Device” assigned to Laser Technology, Inc., Englewood, Colo., and Kama-Tech (HK) Limited, Hong Kong, China assignees of the present invention, the disclosure of which is herein incorporated by this reference in its entirety.
While generally representative of the current state of the art in such designs, the afore-mentioned '504, '314, and '894 patents all describe systems of lenses and prisms which are relatively complex to implement, space inefficient, as well as costly to manufacture, assemble and align. Therefore, a need exists for a high precision, high performance optical system and beam pathway design for a laser-based range-finder which provides significant advantages over conventional designs while nevertheless providing an accurate foundation for a compact, professional range-finder having excellent beam transmission/reception and optical properties for use in surveying or other demanding range-finding applications.